asan: Don’t pad the CrashpadInfo struct with a red zone

client/crashpad_info.cc

 // Copyright 2014 The Crashpad Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
@@ skipping 48 matching lines @@
 // This may result in a static module initializer in debug-mode builds, but
 // because it’s POD, no code should need to run to initialize this under
 // release-mode optimization.
 #if defined(OS_MACOSX)
 
 // Put the structure in __DATA,__crashpad_info where it can be easily found
 // without having to consult the symbol table. The “used” attribute prevents it
 // from being dead-stripped.
 __attribute__((section(SEG_DATA ",__crashpad_info"),
                used,
-               visibility("hidden"))) CrashpadInfo g_crashpad_info;
+               visibility("hidden")
+#if __has_feature(address_sanitizer)
+// AddressSanitizer would add a trailing red zone of at least 32 bytes, which
+// would be reflected in the size of the custom section. This confuses
+// MachOImageReader::GetCrashpadInfo(), which finds that the section’s size
+// disagrees with the structure’s size_ field. By specifying an alignment
+// greater than the red zone size, the red zone will be suppressed.
+               ,
+               aligned(64)
+#endif
+             )) CrashpadInfo g_crashpad_info;
 
 #elif defined(OS_WIN)
 
 // Put the struct in a section name CPADinfo where it can be found without the
 // symbol table.
 #pragma section("CPADinfo", read, write)
 __declspec(allocate("CPADinfo")) CrashpadInfo g_crashpad_info;
 
 #endif
 
@@ skipping 12 matching lines @@
       simple_annotations_(nullptr)
 #if defined(OS_WIN)
       ,
       exception_pointers_(nullptr),
       thread_id_(0)
 #endif  // OS_WIN
 {
 }
 
 }  // namespace crashpad